Signal transduction device

ABSTRACT

A device that non-invasively detects objects beneath or around the foot or a foot position and transmits signals which are processed and then output via an output device on a skin surface not affected by a neurological deficit, such as the hands or thighs. This device is suitable for subjects with diabetic neuropathy who have lost sensation in their feet and are at risk of punctures, cuts or other physical damage and at risk of sprains, strains or falls due to lack of an ability to detect objects underfoot and foot position.

BACKGROUND OF THE INVENTION Field of the Invention

The invention involves the fields of medicine, particularly neurology,physical therapy, and prosthetic devices.

Description of Related Art

Diabetes mellitus is quite common in the population of Saudi Arabia andhas a prevalence of about 20-25%. Diabetes mellitus affects bodilymetabolism and causes high blood glucose. Chronic levels of high bloodsugar can detrimentally affect multiple organs in the body including thenervous system. Dysfunction of the nervous system caused by diabetesmellitus often occurs first in the feet and lower limbs where theaffected nerves cannot function properly leading to diabetic neuropathyand loss of sensation. This poses an ongoing risk to a person who haslost sensation because they cannot easily detect sharp objects, blistersand other physical damage to the feet. Moreover, the loss of sensationmakes walking difficult and increases the risk of falls. There is anongoing unsatisfied need for ways to compensate for loss of sensation infeet and lower limbs.

Devices for receiving and emitting signals are known in the field ofprosthetic devices. However, these are unsuitable for natural limbs thathave lost sensation because they generally require hardwiring orsurgical implantation of electrodes into the skin of a person fittedwith the prosthetic device. Electrodes have been connected between anon-biological, prosthetic hand and corresponding nerves of the hand,median, radial and ulnar nerves in the mid forearm; Tan, et al., SciTransl. Med. 6(257:257ra138, A neural interface provides long-termstable natural touch perception (2014). Flat interface nerve electrodesor FINEs were implanted on the median and ulnar nerves and afour-contact spiral electrode was implanted on the radial nerve; see,respectively, Tyler D J, Durand D M. Chronic response of the rat sciaticnerve to the flat interface nerve electrode. Ann Biomed Eng. 2003;31:633-642; and Naples G G, Mortimer J T, Scheiner A, Sweeney J D. Aspiral nerve cuff electrode for peripheral nerve stimulation. IEEE TransBiomed Eng. 1988; 35:905-916. Other work involved the use ofsomatosensory prosthetics built with neural interfaces that providesomatosensory feedback between prosthesis and nerves of the hand,median, ulnar and radial nerves; Tyler, et al., (2015). Other researchhas been directed to myoelectric prostheses which stimulate peripheralnerves using implanted cuff electrodes proportional to forces on thethumb, index and middle fingers of a prosthetic hand; Schiefer, et al.(2016). For example, an artificial hand attached to intrafascicularelectrodes implanted into the stumps of median and ulnar nerves has beenused to provide object discrimination in patients with upper limbamputation; see Horch K, Meek S, Taylor T G, Hutchinson D T. Objectdiscrimination with an artificial hand using electrical stimulation ofperipheral tactile and proprioceptive pathways with intrafascicularelectrodes. IEEE Trans Neural Syst Rehabil Eng. 2011; 19:483-489. Fan,et al., Transactions of Neural Systems and Rehabilitation Engineering16: 270 (2008) describe a haptic feedback system for lower-limbprosthesis.

As mentioned above, the methods described above are used withartificial, non-biological prosthetic hands and not with natural limbsthat have lost sensation, such as the feet of a subject with diabeticneuropathy. For a subject who has not lost a limb and who does not needa prosthetic foot or leg it is undesirable to invasively implantelectrodes directly into the skin as this leads to irritation,discomfort, pain and infection.

Some work has been performed with non-prosthetic devices. Sykes, U.S.Pat. No. 6,958,681, describes an electrical device that has a pushbutton switch mounted on the heel of a shoe connected to a vibrator on aleg to provide a signal when a foot is in contact with a surface.Fleischer, et al., U.S. Patent Pub. 2015/0216449 describes a wirelesssensor for detecting and monitoring pressure on a body part. Wiggin, etal., U.S. 2013/029674.1 describe ankle-foot orthotic devices withvibrotactile feedback. Tanaka, et al., U.S. 2007/0073196, describe adevice for applying sensory stimulation to skin. As apparent from priorwork, a new system or device that provides higher quality outputinformation in an easy to perceive sensory form to subjects who havelost sensation in their feet and lower limbs is needed. In view of theabove, the inventors developed a system that provides information thataccurately maps conditions at different positions on the foot or lowerlimb and permits a use to sense these inputs on a part of the body notimpaired by neurological map can take the same shape and orientation ofthe foot parts thus allowing a user to distinguish the exact site ofsensor input on the foot which is output as a sensation on the thigh. Inaddition to that the user can feel the different types of sensationmodalities, as sharp or dull sensation, cold or heat, thus preventingdamage from environmental hazards underneath the user's feet. Also, thedevice may notify the patient by alarm for mispositioning the foot sothat the now aware patient can prevent falls or pressure ulcers. Thedevice can surround the whole foot so that it may feel the size of shoesfor example and other sensations.

In view of these differences and limitations on prior technologies, theinventor sought to develop a safe, non-invasive system to permitsubjects with peripheral neuropathy in the feet to restore sensation,thus permitting a patient to again perceive dangerous objects andprecarious foot positions.

BRIEF SUMMARY OF THE INVENTION

The invention involves a device and system for compensating for loss ofsensation in the feet and lower limbs associated with diabeticneuropathy and similar conditions. It uses pressure sensors as well assensors measuring other important parameters placed on the feet andlower limbs to receive information and relay it via a processor tooutput devices positioned on the thighs or another skin surface that hasnot loss sensation. The output devices are arranged in a way tofacilitate understanding of the tactile output signals, for example, bymapping and corresponding input sensor locations to correspondinglocations on the thighs or other body surface. This system includessensors to receive signals that the feet and lower limbs of a subjectreceive poorly or not at all due to neurological dysfunction, aprocessor for receiving, sorting, transducing or amplifying thesesignals, and output devices which produce tactile signals on a body partnot affected by the neurological dysfunction, such as on the thighs of asubject wearing or otherwise equipped with the system. In contrast toexisting systems for artificial prosthetics, the system of the inventiondoes not require its input sensors or to be implanted into the body anddoes not require replacement of a natural limb with a prosthetic device.Rather, sensors can be adhered to the skin or integrated into clothingin a manner that positions the input sensors over body parts lackingsensation and positions output devices over non-dysfunctional body partsthat can receive tactile sensations. For example, it may be incorporatedinto one or more stretchable garments that cover the feet and lowerlimbs and thighs or into interconnected garments such as socks or shoescontaining input sensors connected via wires or in some embodiments,wirelessly, to output devices in clothing positioned over the thigh. Theterms “system” and “device” may be used interchangeably, however, insome embodiments a “device” may describe physically-connected inputsensors, processor(s) and output devices and a “system” can describethese elements (or additional ancillary elements) in which at least oneconnection is a remote or wireless connection.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 describes one configuration of the system of the invention withinput pressure sensors (100) positioned over the feet, connected viawires or cables (200) to a processor (300) positioned on the calf, andoutput devices (400) on the thighs. Output devices may be configuredwithin a foot-shaped area of the thigh (500) to correlate with placementof input sensors on the foot. In this embodiment, the system isintegrated by means of wires conduct signals between the components andthe output devices are arranged in a series of horizontal stripes whichreceive signals from different sensors (100) on the feet. Position ofvirtual foot containing output devices: toe downward (A), toe upward(B).

FIG. 2. Dorsal and plantar foot surfaces on which sensors may be placed.

FIG. 3. Dorsal thigh and upper leg surfaces on which output devices maybe arranged.

FIG. 4. Hand and finger surfaces on which output devices may be placed.

FIG. 5. Block diagram showing an interrelationship of the elements inone example of the invention. In a more basic form, input sensors (710)are connected to processing unit (740) and to sensory output devices(750).

DETAILED DESCRIPTION OF THE INVENTION

Users.

A user of the system or device as described herein generally is not ableto directly perceive sensations signaling injury or a risk of injury dueto a loss of sensation in the lower limbs or in portions of the lowerbody such as the feet and ankles. The loss of sensation leads to anincreased risk of injury from abrasions, cuts and puncture wounds,neuropathic ulcers, pressure ulcers, diabetic foot syndrome, and othertrauma because objects causing such injury are not felt. The presence ofsmall stones or other abrasive, cutting, puncturing or blisteringobjects is not detected leading to injury. An individual with diminishedor loss of lower body sensation may also be incapable of detectingwhether the foot is too hot or too cold resulting in risk of burn orfreezing injury or ischemic injury due to loss of circulation.

Loss of sensation makes it difficult for a person to detect the positionof a foot or ankle, such as whether a foot is level with the ground orwhether it is firmly supported by a surface thereby increasing the riskof a fall.

Individuals with a loss of sensation in the feet and lower limbs includethose with diabetes or diabetic neuropathy, alcoholism including chronicalcohol abuse, Charcot-Marie Tooth disease, frostbite, stroke, crushingor other physical injuries, Guillan-Barré syndrome, herniated disks,Lyme disease, Morton's neuroma, multiple sclerosis and loss of sensationassociated with chemotherapy, radiation exposure, spinal cord injury,and vasculitis. These subjects can particularly benefit from using thesystem and device of as disclosed herein.

Device/System.

A wired device and/or system with at least one wireless connection asdescribed herein compensates a user for lost sensation in the foot,ankle or lower limb. This is accomplished by incorporating one or moresensor inputs on and around the foot, ankle and lower limb that detectpressure, punctures, weight, moisture, conductance, temperature,including skin temperature, and positional signals and convey thesesignals to the user, for example, by an output of tactile signals on theuser's thigh or other bodily surface that can perceive the tactilesignals.

In one embodiment as shown by FIG. 1 the device will include inputpressure sensors on the foot, ankle or lower limbs (100) linked via aprocessor (300) to output devices (400) on the thighs or another sensatebody surface. Positioning the output devices for each foot on separatethighs permits the user to easily discriminate between signals receivedfrom separate feet. Similarly, output devices for each foot may beattached to skin surfaces on the right or left sides of the body. Insome embodiments, output devices will be positioned on the front of thethighs, in others on the back of the thighs, and in still others onanterior, lateral, and/or posterior surfaces of the thigh, for example,sensors on the plantar surface of the foot may deliver signals to outputdevices on the posterior portion of the thighs and sensors on the dorsalsurface of the foot can deliver signals to output devices on theanterior portion of the thighs.

Input Sensors.

Any type of input sensor suitable for attachment to the foot, ankle orlower limb may be selected depending on the habits, lifestyle andspecific needs of the users. Typically, these sensors are removablyattached, do not require surgical implantation, and do not damage theskin. Sensors can be worn under or around the foot, ankle or lower limbsand include piezoresistive, piezoelectric, capacitive andelastoresistive sensors as well as arrays of pressure sensors, straingauge rosettes, and biologically inspired sensors. Any number of inputsensors may be mounted on the foot, ankle or lower limb as necessary toprovide input needed by a particular user. For example, 1, 2, 3, 4, 5,6, 7, 8, 9, 10 or more input sensors, sensor arrays or sensor grids, maybe placed on or around the foot, ankle or lower limb. Fewer sensors maybe used for a subject with partial or limited neuropathy.

Any type of input sensor may be employed. Preferably the device includesor is based on the use of pressure sensors which indicate an amount ofpressure on a portion of a toe, foot or ankle, for example, to assist auser to determine whether a shoe is loose or tight or determine theamount of pressure or weight placed on different parts of the toe, foot,sole or ankle. Thus, a basic device may include pressure sensors placedon different portions of the foot such as the toe and heel or any or allof the portions of the foot innervated by the nerves described by FIG.2. For example, input sensors that measure pressure may be placed onplantar surfaces 1, 4, 5, 6 and 7 and/or on dorsal surfaces 1, 2, 3 and7 shown by FIG. 2.

In some embodiments, output devices are placed on either the front orrear skin of the thighs. These output devices may be configured as avirtual foot surface A or B as shown by FIG. 1. Output devices areplaced in positions within surfaces A or B that correspond to placementof input sensors on the right plantar surface (sole) of the foot and/ordorsal surface of the foot. Reflected symmetrical areas A′ and B′ (notshown) can be imposed on the left thigh which corresponding to sensorinputs from the left foot.

Output device placement using virtual area A and A′ has the advantage ofaligning area A with the right foot below it and area A′ with the leftfoot below it. Output device placement using virtual area B and B′ hasthe advantage of aligning sensory input from sensors at the distal partof the feet with the upper, generally wider, part of the thigh.

In other embodiments, output devices are placed on both the front andrear surfaces of the thighs, for example, where input sensors placed onthe plantar surface (sole) of the foot activate output devices placed onthe rear of the thigh and where input sensors placed on the dorsalsurface of the foot activate output devices on the front of the thigh;or vice versa, where input sensors placed on the plantar surface (sole)of the foot activate output devices placed on the front of the thigh andwhere input sensors placed on the dorsal surface of the foot activateoutput devices on the rear of the thigh. In these embodiments,corresponding virtual foot outlines A and B appear on both the front andrear of the thighs. For example, virtual areas A and B as shown in FIG.1 (or A′ and B′ on the left thigh) may extend to define both front andrear surfaces of the thigh.

Preferably, both input sensors and output devices are positioned overareas of the skin innervated by preselected nerves to facilitatelocalization of sensory inputs from the input sensors. The alignment ofinput sensor signals placed on areas of the foot innervated byparticular nerves with areas of thigh innervated by particular nerves inthe thigh will depend on whether virtual foot configuration A or B (orA′ or B′) is selected.

Linkage between input sensors positioned over areas of skin on the footinnervated by particular nerves and areas of skin on the thighs or handsinnervated by particular nerves may be based on approximate anatomicalcorrespondence between positions of the input sensors on the foot andareas. Some non-limiting examples of correspondence between inputsensors and output devices on the hands and thighs are provided by theTable below. This linkage provide more accurate site of sensationcorrespondence, due to that anatomically innervated area feels thesensation of 2 points if it is apart enough to be sensed by 2 branchesof the sensing nerve. For example to distinguish tow points of pressurein the same innervated area should be different in the force so that thenerve will feel them, or there should be an enough distance thatdifferent branch of the nerve is innervating these different 2 areas, soit is sensed as 2 stimuli. This area to discriminate 2 points ofsensation differ from one part of the body to another, it is moreaccurate in distal parts than proximal, for example the tip of fingersare most sensitive part to 2 point discrimination and this area becomebigger as we go proximal for the arm for example.

Output devices Thigh Output devices Thigh Output devices Input sensor(A, virtual toe down) (B, virtual toe up) on Hand Dorsal Location ofLocation of Location of output surface output device: output device:device: dorsal of foot (front thigh) (front of thigh) surface of hand 110, 12, 13 11, 12 33, 34, wrist 2 10, 12 12 34 3 10, 11, 12 10, 11, 1233, wrist 7 11, 12 10 35 Location of Location of Location of Location ofoutput input sensor output device output device device: palmar (plantar)(rear of thigh) (rear of thigh) surface of hand 1 12, 14 11, 12 31, 32 412, 13, 14 13 31, 32 5 10 10 30 6 13 12, 13 Proximal portions of 30, 31,32, or wrist 7 10 10, 13 30

Those skilled in the art will recognize that input sensors and outputdevices may be further localized to corresponding subsections of theareas described by FIGS. 2, 3 and 4. For example, an input sensor on thebig toe may be linked to an output device positioned on the thumb or aninput sensor on the heel may be linked to an output device positioned onthe proximal portion of the hand or on the wrist.

Providing anatomical correspondence based on natural innervation betweenthe positions of the input sensors and the output devices, permits auser to more easily identify the location of input received from thefoot.

Similarly, foot-shaped arrays of output devices on the thighs linked toa similar array of input sensors on the feet assist a user in easilyidentifying the location of input received by the sensors.

These input sensors detect pressure or other signals, such astemperature, weight and pressure, humidity, position, feet alignment,shoes tightness, etc. without piercing the skin or by direct or surgicallinkage to a user's nervous system. For example, input sensors typicallywill not penetrate the subcutaneous tissue, dermis, or inner layers ofthe epidermis, such as the stratum basale the stratum spinsum or stratumgranulosum, and preferably do not breach any sublayer of the epidermis,the outermost layer of skin. Such input sensors may be positioneddirectly on the outer surface of the skin and held in place by awearable garment, wrap or patch which may optionally include an adhesiveto facilitate attachment of the input sensor to a particular location onthe skin. In many embodiments the removal of the input sensor affectsthe skin no more than removal of a bandage or adhesive bandage.Typically, when the input sensors are removed from the skin of a userthey leave no pierced or damaged skin.

Pressure sensors include those built from conductive rubber, leadzirconate titanate (PZT), polyvinylidene fluoride (PVDF), PVDF-TrFE,FET, and metallic capacitive sensing elements.

Pressure sensors or other sensors designed to detect materials capableof puncturing or lacerating the feet may contain one or more sensitivelayers that when partially or completed punctured or lacerated deliver asignal to an output device to warn the wearer of the danger of apuncture wound or laceration.

Biologically inspired input sensors include those which can detectvibration, force, moisture, and/or heat transfer. Input sensors maydeliver a binary signal such as a signal that pressure, temperature,moisture or other parameter is above or below a preselected threshold ormay deliver a signal proportionate to the signal received, for example,a signal that is progressively more intense with increasing pressure,temperature, moisture or other parameter detected by an input sensor.Input sensors include those described or referenced byhttps://en.wikipedia.org/wiki/Tactile_sensor (last accessed Feb. 5,2019, incorporated by reference).

Input sensors can be selected that determine the relative pressure orcompression on different parts of the foot thus avoiding blistering orloss of circulation in the toes, foot or ankles due to external pressurefrom too-tight shoes or other foot coverings.

Input sensors may be selected to recognize foot position, balance basedon differential pressure patterns on the sole, foot position andmisalignment or malposition of the foot with regard to the ankle andleg, for example, they provide input which the processor can interpretas whether the foot is level or in a position suitable for walking orstanding. Positional sensors such as those used in body motion suits maybe used. These sensors provide input that reduces the risk of a fall orsprain to the foot.

To facilitate recognition and discrimination among signals received fromdifferent parts feet, input sensors may be selectively placed ondifferent foot, ankle or lower limb surfaces that in healthy individualsare innervated by different nerves. In a subject lacking sensation inthe feet and lower limbs such placement reiterates natural reception ofsignals by the feet, ankles and lower body. Thus input sensors on thefoot may be placed next to a foot surface enervated by the medialplantar nerve, the medial plantar nerve and the lateral plantar nerve,the by the medial plantar nerve, the lateral plantar nerve, the tibialnerve and/or the sural and saphenous nerves; see FIG. 2. Depending onthe individual user's needs, input sensors may be placed on one or morefoot surfaces innervated by these nerves and linked to correspondingpositions on the thigh or other surface to which output devices areattached. In some embodiments, inputs from a surface innervated by aparticular nerve in foot or lower limbs will be linked to thigh skinsurfaces innervated by a particular nerve of the thigh, for example,input from a sensor on the sole of the foot innervated by the medialplantar nerve (4), can be delivered to an output device positioned onthe thigh on skin innervated by the posterior ramus or rami (17) or theobturator nerve (19).

Signal Processing.

To facilitate signal delivery between input sensors and output devicessuch as devices that deliver a tactile signal to skin on a thigh, thesystem and device can include a signal processing unit or signaltransducing unit to receive signals from input sensors and transmit themto output devices in a form that activates the output device. Theprocessor may transform one type of signal received from an input sensorinto another type of signal that an output device receives. As describedin the Example, some embodiments of the invention also involve signalstorage and/or computer processing and can include wireless transmissionof a signal. The processing may involve sorting the sensation signals asordinary or high risk signals that may cause risk of fall or potentialfor injury and alarm the user and instruct him accordingly.

Tactile or Other Signal Outputs.

Output devices include outputs which receive and output tactilesensations such as touch and force. Tactile interface devices caninclude vibration motors (e.g., eccentric rotating mass (ERM) devices),Linear Resonant Actuators (LRAs), piezoelectric devices, and/or anyother suitable devices (and/or combinations thereof, such as hybriddevices incorporating both ERM and LRA elements). The device(s) canadditionally or alternatively be operable to provide one or more of:auditory stimuli, electrical stimuli, visual signals or displays, andany other suitable form of stimulus, that alarming for risky positionsof fall, and instructions that may help the user in differentsituations.

Typically, output devices are arranged in a familiar, logical, orrecognizable pattern that helps the user identify the source of thesensor input, for example, the pattern of distribution of input sensorson a foot may correspond to a pattern of output devices on the thigh;see FIG. 1 at reference character (500) which shows a virtual foot whichis superimposable on the surface of a thigh. In other embodiments outputdevices may be arranged in lateral bands which correspond tofront-to-rear or rear-to-front (horizontal stripes), or side-to-side(vertical stripes) sensor placement on the foot, see reference character(410), from front-to-back or from side-to-side.

In a typical embodiment, the output devices are placed on or around thethighs in positions corresponding to similar positions on the foot. Forexample, pressure input sensors placed on a portion of the footenervated by the medial plantar nerve (4) may transmit signals to outputdevices on the surface of the posterior portion of the thigh enervatedby the posterior cutaneous nerve; and, pressure sensors on the soleinnervated by the lateral plantar nerve (5) or sural nerve (7) maytransmit signals to output devices posterior surface of the thighenervated by the lateral cutaneous nerve; and, pressure sensors on the adorsal portion of the foot enervated by the superficial peroneal nerve(3) or deep peroneal nerve (2) may transmit signals to output devicesplaced on an anterior surface of the thigh enervated by the femoral orlateral cutaneous nerve. Depending on the condition and preference ofthe user, any other correspondence between areas (1)-(7) in FIG. 2 andareas (10)-(14) in FIG. 3 or areas (30)-(35) in FIG. 4 may be to linksensor input signals to output devices.

In another embodiment, instead of delivering signals from input sensorsto the thigh, these signals may be delivered to positions on the handcorresponding to foot surfaces, for example, by incorporating outputdevices into gloves containing tactile output devices. Linkage betweenfoot surfaces innervated by particular nerves and hand surfacesinnervated by particular nerves may be employed. Input sensorspositioned on skin innervated by nerves identified by (4), (5) and (6)in FIG. 2 may be delivered to the hand on skin at positions (30), (31)and (32) which are respectively innervated by the ulnar, median andradial nerves. Similarly signals from input sensors on the dorsalsurface of the foot in areas (3), (2) and (7) in FIG. 2 can be deliveredto output devices on areas (33), (34) and (35) shown in FIG. 4. Signalsfrom input sensors may be conveyed to output devices in gloves directlyvia wires, for example, wires embedded in a body suit or an undergarmentthat covers the body between the input sensors and output devices, ormay be conveyed via wireless signals to a receiver in or adjacent to thegloves containing output devices. In some embodiments, both the inputsensors and output devices are embedded in a stretchable or elasticgarment that positions the input sensors over the desired areas of skinand also positions the output devices over corresponding areas of skinon the thighs or hands. The garment can link signals received from theinput sensors to the output devices via one or two processors which mayalso be built into the garment or worn separately by the user, forexample, worn around the calves of the leg as shown by FIG. 1. When twoprocessors are used, they may independently process input signals fromthe right and left legs, respectively. In other embodiments, a singleprocessor connected to input devices in both legs may be used.

Pressure sensors placed on a portion of the foot innervated by themedial plantar nerve (4) may transmit signals to output devices on thesurface of the palm innervated by the median nerve, pressure sensors onthe sole innervated by the lateral plantar nerve (5), calcaneal branchof the tibial nerve (6) or sural nerve (7) may transmit signals tooutput devices on a surface of the palm innervated by the ulnar nerve;and sensors on a dorsal portion of the foot innervated by thesuperficial peroneal nerve (3) or deep peroneal nerve (2) may transmitsignals to output devices placed on a hand surface innervated by theradial nerve.

Other linkage schemes between surfaces of the foot innervated by thesaphenous (1), deep peroneal nerve (2), superficial peroneal nerve (3),medial plantar nerve (4), lateral plantar nerve (5) calcaneal branch ofthe tibial nerve (6) and sural nerve (7) nerves and hand surfacesinnervated by the ulnar, median and radial nerves may be selected basedon the nature of the neurological deficit and the preference of asubject. Any other correspondence between areas (1)-(7) in FIG. 2 andareas (30)-(35) in FIG. 4 may be selected to link sensor input signalsto output devices.

An output device may deliver a single type of signal, for example, atactile output corresponding to the amount of pressure on acorresponding input sensor, or more than one type signal, for example, atactile output indicating a degree of pressure on the input sensor aswell as the amount of moisture, conductance or temperature on the inputsensor. Output may be provided by a single output device that deliversone or more tactile output signals to the skin, for example, tactileoutputs at different frequencies that correspond to qualitativelydifferent sensor inputs such as pressure, temperature, moisture, etc.Alternatively, individual output devices that deliver tactile outputsdedicated to one type of sensor input, such as pressure or temperaturebut not both, may be arranged at the same, adjacent or differentlocations on the thigh or other skin surface.

Positional sensors on the foot alone or in combination with otherpositional sensors on the foot, may indicate whether the sole of thefoot is level, the height of a foot with respect to the other foot,whether the foot is in motion or stationary, gait and length of stride,whether only part of the foot is in contact with a surface, or relativepitch, roll or yaw of a foot, such as the angle made by the toe and heelwith respect to a surface, pronation or supination of a foot, or whetherthe foot exhibits in-toeing (pigeon toe). Position of a foot may beindicated by a tactile signal delivered via an output device or may bedelivered visually or aurally, for example, by one or more flashinglights or alarms indicating when a foot is not level, not fully incontact with a surface or otherwise malpositioned. In some embodiments,wearable input sensors are used for gait event detection. These includefootswitches (e.g. pressure insoles or force sensitive resistors), jointangle measurement sensors such as a potentiometer, goniometer orelectromyography (EMG) sensors, and other inertial sensors such asaccelerometers, gyroscopes and their combination which is known as aninertial measurement unit. Inputs from these sensors may be processedusing a gait event detection algorithm to help a patient maintain aproper foot position and gait or correct an improper one.

In some embodiments, sensors such as those used in body motion suits maybe incorporated into the device described herein. In some embodiments,the relative position of a foot may be transmitted to an output displaysuch as to a wireless phone screen or a wearable computer having visualor aural output. In some embodiments, motion capture sensors may be usedto provide positional information for a foot, ankle or lower limb.

Clothing.

In some embodiments, input sensors and output devices are embedded intoa wearable form. Thus input sensors may be incorporated into a sock orsock-like covering which can surround all surfaces of the foot includingthe sole, the sides of the foot and the top surfaces of the foot andankle. In other embodiments, this sock-like portion may be part of anintegrated garment that also covers the thighs or other parts of thebody and contains tactile output devices, such as leggings, body wrap,leotards, unitard, unisuits, Zentai suits, compression garments,wetsuits, skinny jeans, slacks, yoga pants, foundation garments, motioncapture suits, hosiery, support hose, swimwear, underwear, or otherclose-fitting clothing that covers the feet, ankles and/or thighs andbrings these surfaces into contact with input sensors or tactile outputdevices. In some embodiments, such as that depicted by FIG. 1 the inputsensors and output devices may be incorporated into separate pieces ofclothing, such as into socks or foot coverings and into clothing thatfits around the thighs. A processing device is preferably placed betweenthe input sensors and the output devices as also shown by FIG. 1 and maybe incorporated into clothing or worn on the calves, legs or other partsof the body. In some embodiments input sensors will deliver signals tooutput devices in gloves or to local or remote displays or devices.Wearable devices and clothing may contain stretchable fabrics such asSpandex® (elastane) and Spandex® blends which are known and incorporatedby reference to https://_sewguide.com/stretchy-fabric/ orhttps://_en.wikipedia.org/wiki/Spandex (each last accessed Feb. 7,2019).

Specific embodiments of the invention include, but are not limited tothe following:

A device mounted on a human leg comprising a power source and at leastone input pressure sensor, operably connected to at least one processor,operably connected to at least one output device that delivers a tactilesignal to the skin or an audible alarm or visual display, wherein thedevice is configured so that the at least one input pressure sensor isadjacent to skin on the foot or ankle and so that the at least oneoutput device is adjacent to skin on the thigh or wherein the outputdevice produces an auditory warning or visual display. This device maybe configured to position the at least one input pressure sensor on thedorsal surface of a foot or configured to position the at least oneinput pressure sensor on the plantar surface of a foot. Any portablepower source may be incorporated into the device of the invention,including into a stretchable garment that contains the input sensors,processor and output devices and covers the feet and thighs or hands (orother parts of the body where output devices may be positioned).Portable power sources include batteries, such as alkaline or lithiumbatteries, stretchable batteries, and rechargeable batteries, fuel cellsincluding those that use glucose, physiological fluids, and otherbiofuels, photovoltaic or RF harvesters including those that harvestbody heat, supercapacitors, and solar cells.

The device can include multiple input pressure sensors positioned to beadjacent to at least three, four, five, six or seven different surfacesof the foot innervated by different nerves. More than one input sensormay be placed in an area of skin innervated by a particular nerve.

It can include at least one input pressure sensor positioned to beadjacent to a surface innervated by the saphenous nerve or adjacent to asurface innervated by the sural nerve. It can include input sensors onskin surfaces innervated by the medial plantar, lateral plantar,saphenous, sural and tibial nerves.

In some embodiments, the device will include at least one input sensorthat detects a puncture or laceration of the sensor for example a sensorwith multiple layers that detect the presence of a puncturing object. Inother embodiments, the at least one input sensor will detect skintemperature or temperature, moisture of conductance around the food orankle.

In other embodiments, sensors that detect foot or limb position such aswhether a foot is inclined or level with a surface, motion of the footor limb, or distribution of pressure on a foot when standing orstriding.

The device may include at least one input sensor that detects an unsafeor risky foot position and an output device that emits an audible alarmor audible warning when the foot position is not level, not fullysupported by a surface, or is otherwise abnormal. In some embodiments avisual indicator or display may also warn the user of an abnormal orunsafe foot position.

Many embodiments of this device will contain one or more output deviceslocated or positioned on a body surface that does not suffer from lackof sensation such as on the thigh or thighs of a user. Generally, theseoutput devices vibrate or provide other kinds of tactile signals to thisskin surface. There is no limit to the number of output devices placedon the surface of the skin, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10or more output devices may be positioned or array on a thigh or otherbody surface, preferably, in positions that map to the shape of the footon which input sensors are placed. Individual output devices or arrays,rosettes or grids of output devices may be used.

In some embodiments, the device is configured to place at least one ofthe output devices on an area of the thigh innervated by the lateralcutaneous nerve or femoral nerve or configured to place at least one ofthe output devices on an area of the thigh innervated by the posteriorcutaneous nerve.

The device as described herein may include one or more pieces of astretchable fabric that alone or in combination cover the foot, ankleand thigh. For example, the individual sensors and output devices of theinvention may be incorporated into an article of clothing.

Another embodiment of the invention is directed to a method forcompensating for loss of sensation in a foot, ankle or lower limb of ahuman subject comprising clothing the subject with the device asdisclosed herein. Such a human subject may be someone having hasdiabetic neuropathy or another disease, disorder or condition causingloss of sensation in the foot or lower limbs.

Example

The device or system as disclosed herein is preferably one that receivesone or more input signals from sensors on the foot, ankle or lowerlimbs, and provides stimuli through sensory output devices such astactile interface devices positioned over an area of skin notsubstantially impaired by neurological deficit. It may optionallyinclude one or more other elements besides input sensors, processor andoutput devices, including those described in the block diagram of FIG.5. It may include power modules and other power sources, electrical oroptical wiring or wireless communication modules.

The sensor inputs and other device components associated with the outputdevices are preferably disposed in a single device, but can additionallyor alternatively be disposed as a system across a plurality of devices,and/or be disposed in any other suitable manner.

FIG. 5 is a block diagram showing one example (700) of the system of theinvention for receiving input from sensor(s) placed on a foot, ankle orlower limb and receiving and processing these signals to output devicesas described herein. In some embodiments system 700 may include at leastone storage device 790 which can may store a plurality of sensor inputand signal output parameters. The at least one storage device 790 may bea volatile or non-volatile memory device, such as RAM, ROM, EEPROM, orany other device capable of storing data.

The system 700 includes at least one input sensor 710 and preferablymore than one input sensor, for example, sensors placed on dorsal orplantar surfaces of a foot lacking sensation or on surfaces which in ahealthy subject are innervated by different nerves as shown by FIG. 2.The at least one input sensor 710 may measure at least one tactile orother sensory parameter such as pressure, weight, edema, bloodcirculation, temperature, skin temperature, moisture or conductance, andfoot, ankle or limb position. The system 700 typically includesreceiving unit 720 which can receive at least one signal 715 from theinput sensors 710. Each of the at least one input sensor signals 715 maybe communicated from one of the at least one input sensors 710.Alternatively, the receiving unit 720 may include at least onetransceiver that communicates with at least one of the input sensors710. The receiving unit may receive signals from 2, 3, 4, 5, 6 or moreinput sensors 710 placed at different positions on the body, such asover foot surfaces enervated by different nerves. In other embodiments,the receiving unit will receive signals from different types of inputsensors, such as from weight, pressure, position, moisture, ortemperature sensors placed at the same or different positions on thefoot, ankles or lower limbs.

According to an example of the present disclosure, the system 700 mayinclude at least one sensory output device 750. Each of the at least oneoutput devices 750 may deliver a sensory output 755 that can be felt orotherwise detected by a person wearing the device or elements of thesystem. Thus, each of the output devices 750 can provide an output thatcan be detected by the wearer, such as a tactile sensation, an auditorysignal such as a ringtone on a wireless phone or beeper, or visualoutput such as a light or series or array of lights, or a display on ascreen such as a wireless phone screen.

Preferably from the standpoint of providing a tactile signal to restoreloss of feeling in a foot, ankle or lower limb, the at least one outputdevice 750 will deliver a tactile output to skin surfaces on a thigh orthighs of the user. These signals may be binary, such as a signalindicating pressure above or below a threshold value or may beproportionate to the signals received from the input sensors, such as atactile output that increases with increased pressure on the inputsensor or a vibrations of different frequencies indicating differentdegrees of pressure, temperature or moisture.

According to some of the various embodiments, the system 700 may includea processing unit 740 and a tangible non-transitory computer readablemedium 800. The processing unit 740 may include at least one processor.As used herein, physical processor or processor refers to a devicecapable of executing instructions encoding arithmetic, logical, and/orI/O operations. In one illustrative example, a processor may follow VonNeumann architectural model and may include an arithmetic logic unit(ALU), a control unit, and a plurality of registers. In a furtheraspect, a processor may be a single core processor which is typicallycapable of executing one instruction at a time (or process a singlepipeline of instructions), or a multi-core processor which maysimultaneously execute multiple instructions. In another aspect, aprocessor may be implemented as a single integrated circuit, two or moreintegrated circuits, or may be a component of a multi-chip module (e.g.,in which individual microprocessor dies are included in a singleintegrated circuit package and hence share a single socket). A processormay also be referred to as a central processing unit (CPU). In anexample, the one or more physical processors may be in the system 700.In an example, all of the disclosed methods and procedures describedherein can be implemented by the one or more processors. Further, thesystem 700 may be distributed over multiple processors, memories, andnetworks.

The computer readable medium 800 may include instructions that may causethe processing unit 740 to receive at least one signal 730 at block 810.The at least one signal 730 may be received from the receiving unit 720.The computer readable medium 800 may include instructions that may causethe processing unit 740 to detect an abnormal foot position, abnormalpressure, abnormal temperature or other abnormal signal input throughemployment of an estimation method at block 820. Abnormality is measuredin relation to a signal an otherwise identical healthy subject who doesnot suffer from neural dysfunction in the lower limbs such as thatcaused by diabetes or other disability. The estimation method may bebased at least in part on at least one of the input signals 730. Thecomputer readable medium 800 may include instructions that may cause theprocessing unit 740 to select a value for at least one of the parametersat block 830. The value may be based at least in part on at least one ofthe at least one input signal 730. The computer readable medium 800 mayinclude instructions that may cause the processing unit 740 tocommunicate instructions to at least one of the at least one outputdevice 750 at block 840, such as calibration, sensitivity, or resetinstructions. These instructions may be based at least in part on theintensity of inputs from the input sensors.

According to some of the various embodiments, the system 700 may includea transceiving unit 760 that includes at least one transceiver thatincludes at least one transmitter and at least one receiver. Forexample, the transceiving unit may transmit a signal received via theprocessor from a sensor input on the foot to a local or remote alarm orvideo display, such as on a wireless phone or wearable computer. Atleast one of the at least one receiver may be the same as at least oneof the at least one receiver associated with the receiving unit 720.Alternatively, at least one of the at least one transceiver may be thesame as at least one of the at least one transceiver associated with thereceiving unit 720. The transceiving unit 760 may communicate with atleast one remote device 275 employing network 770. By way of example andnot limitation, the remote device 780 may be employed by the user, aremote operator, a medical professional, combinations thereof, and/orthe like. The system 700 may accept operational instructions from theremote device 780. The system 700 may communicate notifications to theremote device 780. In an alternate example, transceiving unit 760 may bedirectly communicatively connected to remote device 780.

According to some embodiments, the at least one storage device 790 maybe communicatively coupled to system 700 through employment of a wiredand/or wireless network. The at least one storage device 790 may bemanaged through employment of a cloud service, a web-based electronicdata capture system, a web application, a mobile device application, amobile device operating system, a virtual machine, combinations thereof,and/or the like.

According to an example of the present disclosure, a sensor signal (715)and a signal (730) may be the same. Alternatively, a signal (730) may bethe baseband signal contained within a sensor signal (715). In someembodiments, the processing unit (740) will calculate foot, ankle orlimb position using signals received from sensors placed at differentpositions on the body, such as over different foot or ankle or limbsurfaces and/or from signals received at different points in time, suchas over the time period of a complete stride or series of strides.

Terminology

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.

The headings (such as “Background” and “Summary”) and sub-headings usedherein are intended only for general organization of topics within thepresent invention, and are not intended to limit the disclosure of thepresent invention or any aspect thereof. In particular, subject matterdisclosed in the “Background” may include novel technology and may notconstitute a recitation of prior art. Subject matter disclosed in the“Summary” is not an exhaustive or complete disclosure of the entirescope of the technology or any embodiments thereof. Classification ordiscussion of a material within a section of this specification ashaving a particular utility is made for convenience, and no inferenceshould be drawn that the material must necessarily or solely function inaccordance with its classification herein when it is used in any givencomposition.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, steps, operations, elements, and/or components, but donot preclude the presence or addition of one or more other features,steps, operations, elements, components, and/or groups thereof.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items and may be abbreviated as“/”.

Links are disabled by deletion of http: or by insertion of a space orunderlined space before www. In some instances, the text available viathe link on the “last accessed” date may be incorporated by reference.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “substantially”, “about” or“approximately,” even if the term does not expressly appear. The phrase“about” or “approximately” may be used when describing magnitude and/orposition to indicate that the value and/or position described is withina reasonable expected range of values and/or positions. For example, anumeric value may have a value that is +/−0.1% of the stated value (orrange of values), +/−1% of the stated value (or range of values), +/−2%of the stated value (or range of values), +/−5% of the stated value (orrange of values), +/−10% of the stated value (or range of values),+/−15% of the stated value (or range of values), +/−20% of the statedvalue (or range of values), etc. Any numerical range recited herein isintended to include all subranges subsumed therein.

Disclosure of values and ranges of values for specific parameters (suchas temperatures, molecular weights, weight percentages, etc.) are notexclusive of other values and ranges of values useful herein. It isenvisioned that two or more specific exemplified values for a givenparameter may define endpoints for a range of values that may be claimedfor the parameter. For example, if Parameter X is exemplified herein tohave value A and also exemplified to have value Z, it is envisioned thatparameter X may have a range of values from about A to about Z.Similarly, it is envisioned that disclosure of two or more ranges ofvalues for a parameter (whether such ranges are nested, overlapping ordistinct) subsume all possible combination of ranges for the value thatmight be claimed using endpoints of the disclosed ranges. For example,if parameter X is exemplified herein to have values in the range of 1-10it also describes subranges for Parameter X including 1-9, 1-8, 1-7,2-9, 2-8, 2-7, 3-9, 3-8, 3-7, 2-8, 3-7, 4-6, or 7-10, 8-10 or 9-10 asmere examples. A range encompasses its endpoints as well as valuesinside of an endpoint, for example, the range 0-5 includes 0, >0, 1, 2,3, 4, <5 and 5.

As used herein, the words “preferred” and “preferably” refer toembodiments of the technology that afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the technology. As referred to herein, all compositionalpercentages are by weight of the total composition, unless otherwisespecified. As used herein, the word “include,” and its variants, isintended to be non-limiting, such that recitation of items in a list isnot to the exclusion of other like items that may also be useful in thematerials, compositions, devices, and methods of this technology.Similarly, the terms “can” and “may” and their variants are intended tobe non-limiting, such that recitation that an embodiment can or maycomprise certain elements or features does not exclude other embodimentsof the present invention that do not contain those elements or features.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper”, “in front of” or “behind” and the like, may be used herein forease of description to describe one element or feature's relationship toanother element(s) or feature(s) as illustrated in the figures. It willbe understood that the spatially relative terms are intended toencompass different orientations of the device in use or operation inaddition to the orientation depicted in the figures. For example, if adevice in the figures is inverted, elements described as “under” or“beneath” other elements or features would then be oriented “over” theother elements or features. Thus, the exemplary term “under” canencompass both an orientation of over and under. The device may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly.Similarly, the terms “upwardly”, “downwardly”, “vertical”, “horizontal”and the like are used herein for the purpose of explanation only unlessspecifically indicated otherwise.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

The description and specific examples, while indicating embodiments ofthe technology, are intended for purposes of illustration only and arenot intended to limit the scope of the technology. Moreover, recitationof multiple embodiments having stated features is not intended toexclude other embodiments having additional features, or otherembodiments incorporating different combinations of the stated features.Specific examples are provided for illustrative purposes of how to makeand use the compositions and methods of this technology and, unlessexplicitly stated otherwise, are not intended to be a representationthat given embodiments of this technology have, or have not, been madeor tested.

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference,especially referenced is disclosure appearing in the same sentence,paragraph, page or section of the specification in which theincorporation by reference appears.

The citation of references herein does not constitute an admission thatthose references are prior art or have any relevance to thepatentability of the technology disclosed herein. Any discussion of thecontent of references cited is intended merely to provide a generalsummary of assertions made by the authors of the references, and doesnot constitute an admission as to the accuracy of the content of suchreferences.

1. A wearable device, comprising: a power source, one or more inputpressure sensors that measure pressure, one or more processors, and oneor more output devices; wherein the at least one input pressure sensoris positioned so that it is next to a preselected area of skin on thefoot or ankle when the device is worn, wherein the at least one outputdevice is positioned so that it is next to a preselected area of skin onthe thigh when the device is worn, and wherein the power source, inputsensor(s), processor(s), output device(s) and power source(s) areinterconnected so that power is delivered to the input sensor(s),processor(s), and output device(s) and so that signals received by theinput sensors are delivered to the processor(s) and subsequentlydelivered to the output device(s).
 2. The device of claim 1, wherein thedevice is configured to position the at least one input pressure sensoron the dorsal surface of a foot.
 3. The device of claim 1, wherein thedevice is configured to position the at least one input pressure sensoron the plantar surface of a foot.
 4. The device of claim 1, wherein thedevice comprises at least four input pressure sensors positioned to beadjacent to at least four different surfaces of the foot innervated bydifferent nerves.
 5. The device of claim 1, wherein the device comprisesat least one input pressure sensor positioned to be adjacent to asurface innervated by the saphenous nerve.
 6. The device of claim 1,wherein the device comprises at least one input pressure sensorpositioned to be adjacent to a surface innervated by the sural nerve. 7.The device of claim 1, wherein the input pressure sensors are positionedto be adjacent to skin surfaces innervated by the medial plantar nerve,the lateral plantar nerve, the saphenous nerve, the sural nerve and thetibial nerve.
 8. The device of claim 1, wherein the input pressuresensor can detect a puncture or tear of or in the sensor.
 9. The deviceof claim 1, further comprising at least one input sensor that detectstemperature.
 10. The device of claim 1, further comprising at least oneinput sensor that detects moisture.
 11. The device of claim 1, furthercomprising at least one input sensor that detects conductance.
 12. Thedevice of claim 1, further comprising at least one input sensor thatdetects a foot position.
 13. The device of claim 1, further comprisingat least one input sensor that detects a foot position and wherein theoutput device produces an audible alarm or a visible signal when thefoot position is not level, not fully supported by a surface, isotherwise abnormal.
 14. The device of claim 1, wherein the at least oneoutput device provides a vibration or other tactile signal to the skinon the thigh.
 15. The device of claim 1, wherein the device isconfigured to place at least one of the output devices on an area of thethigh innervated by the lateral cutaneous nerve or femoral nerve. 16.The device of claim 1, wherein the device is configured to place atleast one of the output devices on an area of the thigh innervated bythe posterior cutaneous nerve.
 17. The device of claim 1 that comprisesone or more pieces of a stretchable fabric that alone or in combinationcover the foot, ankle and thigh.
 18. An article of clothing comprisingthe device of claim 1, wherein each component of the device and wiresconnecting the components together are incorporated into the article ofclothing.
 19. A method for compensating for loss of sensation in a foot,ankle or lower limb of a human subject comprising clothing the subjectwith the article of clothing of claim 18 and activating it to conveysignals from the input sensor(s) to the output device(s).
 20. The methodof claim 19, wherein the subject has diabetic neuropathy.